Saturday, September 21, 2013

New paper finds sea levels rising at less than 4 inches per century, with no acceleration

A new paper finds global mean sea levels rose at only 1 mm/year, equivalent to less than 4 inches per century, over the 203 year period from 1807-2010. The finding is remarkably similar to the sea level rise of 1.1-1.3 mm/yr found by the NOAA 2005-2012 Sea Level Budget, the only sea level budget which reconciles both satellite [altimeters & GRACE] & ARGO float data. The authors also find no evidence of acceleration of sea level rise, which indicates that there is no evidence of a human influence upon sea levels. In addition, the authors find that sea level rise is a localized rather than global phenomenon, with 61% of tide gauge records demonstrating no change in sea levels, 4% showing a decrease, and a minority of 35% showing a rise. This implies relative sea level change is primarily related to subsidence or post-glacial rebound [land height changes] rather than melting ice or steric sea level changes [thermal expansion from warming]. Excerpts:

If SLR is accelerating, sea levels should be nonstationary in first differences, but stationary in second differences. In none of the tide gauges and segments do the Dickey-Fuller and KPSS statistics support the accelerationist hypothesis. [i.e. there was no acceleration]

The substantive contribution of the paper is concerned with recent SLR in different parts of the world. Consensus estimates of recent GMSL rise are about 2mm/year. Our estimate is 1 mm/year. We suggest that the difference between the two estimates is induced by the widespread use of data reconstructions which inform the consensus estimates. There are two types of reconstruction. The first refers to reconstructed data for tide gauges in PSMSL prior to their year of installation. The second refers to locations where there are no tide gauges at all. Since the tide gauges currently in PSMSL are a quasi-random sample, our estimate of current GMSL rise is unbiased. If this is true, reconstruction bias is approximately 1mm/year.

Sea level rise is regional rather than global and is concentrated in the southern Baltic, the Ring of Fire, and the Atlantic coast of the US. By contrast the north-west Pacific coast and north-east coast of India are characterized by sea level fall. In the minority of locations where sea levels are rising the mean increase is about 4 mm/year and in some locations it is as large as 9 mm/year. The fact that sea level rise is not global should not detract from its importance in those parts of the world where it is a serious problem.

Sea level rise is regional rather than global and is concentrated in the southern Baltic, the Ring of Fire, and the Atlantic coast of the US. By contrast the north-west Pacific coast and north-east coast of India are characterized by sea level fall.

TIDE GAUGE LOCATION AND THE MEASUREMENT OF GLOBAL SEA LEVEL RISEMichael Beenstock 1 Daniel Felsenstein 2, Eyal Frank1, Yaniv Reingewertz 11 Department of Economics, Hebrew University of Jerusalem, Jerusalem 91905, Israel2 Department of Geography, Hebrew University of Jerusalem, Jerusalem 91905, IsraelAbstractThe location of tide gauges is not random. If their locations are positively (negatively) correlated with SLR, estimates of global SLR will be biased upwards (downwards). We show that the location of tide gauges in 2000 is independent of SLR as measured by satellite altimetry. Therefore PSMSL tide gauges constitute a quasi-random sample and inferences of SLR based on them are unbiased, and there is no need for data reconstructions. By contrast, tide gauges dating back to the 19th century were located where sea levels happened to be rising. Data reconstructions based on these tide gauges are therefore likely to over-estimate sea level rise. We therefore study individual tide gauge data on sea levels from the Permanent Service for Mean Sea Level (PSMSL) during 1807 – 2010 without recourse to data reconstruction. Although mean sea levels are rising by 1mm/year, sea level rise is local rather than global, and is concentrated in the Baltic and Adriatic seas, South East Asia and the Atlantic coast of the United States. In these locations, covering 35 percent of tide gauges, sea levels rose on average by 3.8mm/year. Sea levels were stable in locations covered by 61 percent of tide gauges, and sea levels fell in locations covered by 4 percent of tide gauges. In these locations sea levels fell on average by almost 6mm/year.Related post on a paper by the same first author:

observations reveal no acceleration of sea level rise over thepast century. In fact, just the opposite appears to be occurring in nature.Holgate (2007), for example, derived a mean global sea level history over the period 1904-2003.According to their calculations, the mean rate of global sea level rise was “larger in the earlypart of the last century (2.03 ± 0.35 mm/year 1904-1953), in comparison with the latter part(1.45 ± 0.34 mm/year 1954-2003).” In other words, contrary to model projections, the meanrate of global sea level rise (SLR) has not accelerated over the recent past. If anything, it’s donejust the opposite. Such observations are striking, especially considering they have occurredover a period of time when many have claimed that (1) the Earth warmed to a degree that isunprecedented over many millennia, (2) the warming resulted in a net accelerated melting ofthe vast majority of the world’s mountain glaciers and polar ice caps, and (3) global sea level rose at an ever increasing rate.”

In another paper, Boretti (2012) applied simple statistics to the two decades of informationcontained in the TOPEX and Jason series of satellite radar altimeter data to “better understandif the SLR is accelerating, stable or decelerating.” In doing so, the Australian scientist reportsthat the rate of SLR is reducing over the measurement period at a rate of -0.11637 mm/year2,and that this deceleration is also “reducing” at a rate of -0.078792 mm/year3 (see Figure 7).And in light of such observations, Boretti writes that the huge deceleration of SLR over the last10 years “is clearly the opposite of what is being predicted by the models,” and that “the SLR’sreduction is even more pronounced during the last 5 years.” To further illustrate theimportance of his findings, he notes that “in order for the prediction of a 100-cm increase in sealevel by 2100 to be correct, the SLR must be almost 11 mm/year every year for the next 89years,” but he notes that “since the SLR is dropping, the predictions become increasinglyunlikely,” especially in view of the facts that (1) “not once in the past 20 years has the SLR of 11mm/year ever been achieved,” and that (2) “the average SLR of 3.1640 mm/year is only 20% ofthe SLR needed for the prediction of a one meter rise to be correct.

The real-world data-based results of Holgate and Boretti, as well as those of other researchers(Morner, 2004; Jevrejeva et al., 2006; Wöppelmann et al., 2009; Houston and Dean, 2011), allsuggest that rising atmospheric CO2 emissions are exerting no discernible influence on the rateof sea level rise. Clearly, SCC damages that are based on model projections of a CO2-inducedacceleration of SLR must be considered inflated and unlikely to occur.

IPCC 2013:"It is likely that GMSL [Global Mean Sea Level] rose between 1920 and 1950 at a rate comparable to that observed between 1993 and 2010"

Sea level rise is a local, not global, phenomenon:

...the authors find that sea level rise is a localized rather than global phenomenon, with 61% of tide gauge records demonstrating no change in sea levels, 4% showing a decrease, and a minority of 35% showing a rise. This implies relative sea level change is primarily related to subsidence or post-glacial rebound [land height changes] rather than melting ice or steric sea level changes [thermal expansion from warming].